Yup, sometimes it’s too easy for me to just slip into work mode when talking about this kind of stuff and I don’t elaborate enough. Thanks for stepping in.
Based on industry rumors I believe the Orion capsule control computers are running VxWorks (I’ve heard that maybe a few boxes are using RTEMS?) All of that source code would have been reviewed, audited, and tested to hell and back.
The day-in-the-life stuff for the astronauts is entirely believable to be Windows. The risk of it failing is so low (medium probability, low impact), it’s what they’d be familiar with, and it’s part of daily life at NASA anyways. Linux is no better when it comes to safety critical components and the astronauts almost certainly wouldn’t want to be dealing with Gnome’s… uniqueness…
You probably can’t find it because you’re mixing mutually exclusive terminology.
A stack is a First-In Last-Out data structure. If your entry criteria is time, the oldest files will persist and the newer ones will get purged first.
If you want to remove oldest files first, you want a First In First Out queue.
Both of these will permanently delete the original file.
Caches are just a copy of real data, sitting somewhere that ideally has faster access times but smaller storage space. The real original file does not get modified. A cache will typically hold onto as much data as it can until it hits some cap, at which point a replacement algorithm is used to select which entry or entries to make space for the newly requested item. Very rarely will a cache delete entries on its own to minimize actively used space, but if they do they will likely just run the replacement algorithm without backfilling the space